piling presentation 06 07 2013.pdf

8/14/2019 piling presentation 06 07 2013.pdf

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Class RoomAt site

Presentation On Pile foundation

Conducted By:- Mr. Pramod Kumar Singh( Sr. Manager

!MRC"CC:#$%o& 'o : )*


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+ntroduction:

When it becomes impossible to provide the suitable surfacefoundation for a structure; the use of pile foundationsbecomes necessary, this situation arose from either the soil

condition or the order of bottom layers, the nature of theloads transferred to the soil or the nature of the site andoperational conditions. Many factors prevent the selection ofsurface foundation as a suitable foundation such as the

nature of soil and intensity of loads, we use the piles whenthe soil have low bearing capacity or in building in water likebridges and dams The main components of the foundationare the pile cap and the piles.


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,unction of iles:

!s other types of foundations, the purpose ofpile foundations is"

To transmit the buildings loads to thefoundations and the ground soil layerswhether these loads vertical or inclined

#iles are a convenient method of foundationfor works over water, such as $etties or bridgepiers.


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Classification of ilesClassification of pile with respect to load

transmission and functional behavior

&nd bearing piles 'point bearing piles( )riction piles 'cohesion piles ( *ombination of friction and cohesion piles


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End bearing piles

These piles transfer their load on to a firm stratum located at a considerable depth below the base of the structure and they

derive most of their carrying capacity from the penetration resistance of thesoil at the toe of the pile . The pile behaves as an ordinary column andshould be designed as such. &ven in weak soil a pile will not fail by bucklingand this effect need only be considered if part of the pile is unsupported, i.e.

if it is in either air or water. oad is transmitted to the soil through friction orcohesion. -ut sometimes, the soil surrounding the pile may adhere to thesurface of the pile and causes /egative 0kin )riction on the pile. This,sometimes have considerable effect on the capacity of the pile. /egative

skin friction is caused by the drainage of the ground water and consolidationof the soil. The founding depth of the pile is influenced by the results of thesiteinvestigate on and soil test.


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Figure 1:End bearing piles Figure 2:Friction orcohesion pile

Friction or cohesion piles Carrying capacity is derived mainly from the adhesion or friction of the soil incontact with the shaft of the pile (fig 2).


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Cohesion piles

These piles transmit most of their load to the soil through skin friction.This process of driving such piles close to each other in groups greatlyreduces the porosity and compressibility of the soil within and around thegroups. Therefore piles of this category are sometimes called compactionpiles. 3uring the process of driving the pile into the ground, the soil

becomes molded and, as a result loses some of its strength. Therefore thepile is not able to transfer the e4act amount of load which it is intended toimmediately after it has been driven. 5sually, the soil regains some of itsstrength three to five months after it has been driven.

Friction piles

These piles also transfer their load to the ground through skin friction. Theprocess of driving such piles does not compact the soil appreciably. Thesetypes of pile foundations are commonly known as floating pilefoundations.


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An extension of the end bearing pile when the bearing stratum is not hard,such as firm clay.

The pile is driven far enough into the lower material to develop adequatefrictional resistance. A farther variation of the end bearing pile is piles withenlarged bearing areas.

This is achieved by forcing a bulb of concrete into the soft stratumimmediately above the firm layer to give an enlarged base.

A similar effect is produced with bored piles by forming a large cone orbell at the bottom with a special reaming tool. Bored piles which are providedwith a bell have a high tensile strength and can be used as tension piles

Combination of friction piles and cohesion piles


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S /0 'C O, CO'S1R0C1+O':

1. Setting out

The position of the pile location is set out with respect to the control points and

checked by &ngineer8s 9epresentative by suitable pin marked on location. 1.+m

deep cutting is done manually at the pile location to check for undergroundutilities..


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# !ri2ing of 1em orary Casing "

)irst .:m depth of the dry boring will be done before driving of temporary casing. Then the

casing will be lifted and lowered in the bore hole. There after driving of casing will be done

by alternate boring and pushing method to the re uired level. ocation of casingerticality *heck"

?ydraulic 9ig is positioned on firm and level ground with use of inbuilt gauges.

*asing driven is checked for plumb up to m from top of casing.


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!rilling "Boring:

-oring operation is done by ?ydraulic 9otary 9ig with the help of @elly and bucket. The

siAe of the bucket shall not be less than 112+ mm for 12:: mm dia pile. In addition to

speeding construction, Tested bentonite should pour into the bore to avoids the

noise ,vibration and side soil collapse problems that influence conventional

foundation. !fter completion of boring the founding level is checked with sounding

chain. Bmmediately after completion of boring the reinforcement cage is lowered,

which was pre=fabricated as per detailed drawing and approved bar bending schedule.

Bf, due to any reason starting of reinforcement cage lowering is delayed 2 ?rs, the bore

hole is cleaned by cleaning bucket and founding level is checked at four location along

the inside circumference of the pile with sounding chain.


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3 Reinforcement Cage 4o5ering "

The bar bending schedule prepared based on approved drawing. 9einforcement is cut

and bent to re uired siAe and shape. 9einforcement steel shall be transported to #ierlocation by trailer and the cage is tied using C.B. -inding wire of gauge 16=2:. ength of

top cage will be as per the full length of reinforcement steel and the bottom piece will be

fabricated as per the length of pile. -ottom cage is lowered inside the bore hole up to

dowel length and the second cage is lifted and lapped as per relevant drawing. ?elical

rings are tied as per drawing and main reinforcement lap is welded at three locations. To

facilitate cage lowering, the cage is lowered up to re uired level and the cage is fi4ed to

pile casing with the help of reinforcement hooks for possible up lift and maintaining cover

at bottom. The side cover for the reinforcement will be maintained by circular concrete

cover blocks fi4ed to helical of cage three blocks per location at 1+:: mm c


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) ,lushing O eration "

Bmmediately after lowering of the cage, tremmie pipes of 2::ertical pump. 3uring flushing contaminated

bentonite will be collected in the steel tank through a fle4ible hose connected to the

tremmie outlet D fresh bentonite will be replaced to maintain the bentonite at re uired

level. )lushing shall be confirmed till the density of the return mud is less than 1.2:gm "176+


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Testing of Bentonite "

3ensity" = The density measured by ?ydrometer. The slurry sample is taken in a 1:::cc

cylinder and the hydrometer is inserted into this suspension. The calibration shown on

the hydrometer directly gives the density in gm


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* Concreting "

Tremmie pipe of 2::


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6 7traction of casing "

!fter the concreting is over the casing is loosened. The casing is e4tracted slowly

without disturbing the pile concrete with e4tra care with the help of crane after :

minutes of last pour and totally after 1 hour.


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SA, 18 PR CA0S1+O'S Working area should be properly barricaded.

!ll site personnel shall be provided with safety helmet, safety $ackets, safety shoes and

other personal safety devices as re uired.

Traffic marshals shall guide the traffic during progress of work.

Traffic shall be diverted as per approved scheme wherever and whenever re uired.

0wing area of the rig should be barricaded or demarcated. Cround stability < leveling will be checked before rig marching.

Everhead electric cables and wires to be checked before marching < swing of rig.

!ll swing alarms and swing lights should be in working condition.

#ile bore muck should not be staked too high.

#ile cage < muck not to be loaded on the barricades.

!ll idle pile bores should be covered with grating.


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piling presentation 06 07 2013.pdf

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